Some argue that millions of Americans are so hooked on television that their viewing habits fit the criteria for substance abuse, as defined in the official psychiatric manual. Choose a young person (age 19 to 25) at random and ask, "In the past seven days, how many days did you watch television?" Call the response X for short. Here is a probability model for the response:
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$$\begin{array} { | l | l | l | l | l | l | l | l | l | }
\hline \text { Days } X & 0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 \
\hline \text { Probability } & 0.04 & 0.03 & 0.06 & 0.08 & 0.09 & 0.08 & 0.05 & ? \
\hline
\end{array}$$ This is a legitimate probability model. Therefore, what is the value of P(X = 7)?

Question

Some argue that millions of Americans are so hooked on television that their viewing habits fit the criteria for substance abuse, as defined in the official psychiatric manual. Choose a young person (age 19 to 25) at random and ask, "In the past seven days, how many days did you watch television?" Call the response X for short. Here is a probability model for the response:
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$$\begin{array} { | l | l | l | l | l | l | l | l | l | } 
\hline \text { Days } X & 0 & 1 & 2 & 3 & 4 & 5 & 6 & 7 \
\hline \text { Probability } & 0.04 & 0.03 & 0.06 & 0.08 & 0.09 & 0.08 & 0.05 & ? \
\hline
\end{array}$$ This is a legitimate probability model. Therefore, what is the value of P(X = 7)?

Quizplus · Accepted Answer

The sum of all probabilities in a probability model must equal 1. Adding the given probabilities: 0.04 + 0.03 + 0.06 + 0.08 + 0.09 + 0.08 + 0.05 = 0.43. Therefore, the missing probability for P(X = 7) must be 1 - 0.43 = 0.57 to make the total sum of probabilities equal to 1.

Some Argue That Millions of Americans Are So Hooked on Television